1. Field of the Invention:
The invention relates to the field of tube connectors for connecting a pressure source with a unit requiring a pressure test such as a refrigeration unit or other device.
2. Description of Prior Art:
The prior art includes inclined ramp arrangements where balls are utilized to exert pressure on a tube by movement down the ramp, gland arrangements to obtain a gripping action, self-locking arrangements and various other sealing connections which have been disclosed in the following patents.
Fischer U.S. Pat. No. 1,031,637 covers a Gripping Device for Rods, Tubes and the Like and involves balls, or rollers, in association with ramp surfaces and is concerned primarily with interlocking two parts at a particular point of adjustment.
U.S. Pat. No. 1,973,809 to Heggem relates to a Tubing Top and is concerned especially with sealing the tubing and tubing top and utilizing tapered slips cooperating with coned surfaces to apply pressure on the tubing.
Maisch U.S. Pat. No. 2,819,733 covers a Tube Sealer and Connector in the form of a quick connect which utilizes a lever as a locking device and applies endwise pressure to obtain a seal between the tube end and a sealing pad.
Racine U.S. Pat. No. 3,738,688 covers a Quick Mount Fitting utilizing a cam lever to actuate a plunger axially to engage a split collet and increase sealing pressure on an elastomeric seal around a tube.
Racine U.S. Pat. No. 3,779,587 for Tube End Fitting also uses a cam lever for applying axial pressure on a tubular plug which seals against the end of a tube and simultaneously clamps a split metal collet around the tube.
Racine U.S. Pat. No. 3,868,132 again makes use of a cam lever to exert axial pressure on a cam and is a continuation-in-part of U.S. Pat. No. 3,738,688.
U.S. Pat. No. 4,059,295 to Helm is for a Tube Coupling and uses a combination of a sleeve surrounding a tube which is clamped around the tube by a U-shaped clip with cams and ramps on the sleeve to exert a clamping action when the tube is moved outwardly of the fitting.
Earlier patents which issued to Tuthill Pump Company, assignee of the present application, include U.S. Pat. Nos. 3,422,980, 3,542,076, 3,727,952, 3,799,207, 3,825,223, and 3,857,414. These patents show different types of tube connectors, some of which seal internally to a tube, some of which seal an open aperture in a container, and others of which seal against the end of a tube as opposed to the present arrangement which seals on the outer periphery of the tube.
None of the foregoing prior patents discloses anything like the action of this invention wherein a piston is biased to cause an initial gripping force on a tube and an initial force on a seal member and then, when the chamber containing the piston is pressurized, the fluid pressure causes a supplemental force against the piston thereby simultaneously increasing the gripping force and the sealing force.